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Health Chapter Seven.docx

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Lawrence Murphy

Chapter 7: Food, Eating and the Environment Eating and Obesity: - Eating and drinking are social activities that are rich in symbolic, moral and cultural meanings - Balance between energy input and expenditure have critical importance - Habits are influenced by an interaction of processes that include conditioning, customs, culture and environment (climate change) - Health action at the level of policy and regulation is very important - The World Health Organization predicts there will be 2.3 billion overweight adults in the world by 2015 and more than 700 million of them will be obese - Voluntary agreements with industry have proved completely ineffective - Obesity has multiple causes: genetic predisposition, culture, diet and inactivity - Obesogenic diets are becoming very common in poor countries - Obesification is also occurring at lower income levels - Dumanovsky et al. (2009) concluded that menu calorie posting may help awareness, but reducing portion sizes and changing popular combination meals would be best - Food industry uses strategies to maintain their profits:  Persaude people to consume more food  Increase serving size and adding price inducements to order larger sizes  Opening up markets in developing countries  Substituting agricultural products with efficient artificial foods  Adding sugar, salt, fats and oils to enhance flavour and look - Income is strongly associated with dietary quality - Higher stress associated with more fatty food intake, less fruit and vegetable intake, more snacking and a reduced likelihood of eating breakfast - Demand for milk and meat will almost double between 2000 and 2050 - Biological influences on body fat levels include age, sex, hormonal factors and genetics - Fat gene: MC4R alleged to play a role in regulating food intake and energy balance—associated with higher intake of total energy, dietary fat, greater long-term weight change and increased risk of diabetes Evolutionary Perspective: - Genetic make-up of contemporary humans remains adapted to a nomadic existence of gathering and hunting - Because phylogenetic evolution is slow, the genetic make-up of contemporary humans remains adapted to a nomadic existence of gathering and hunting - Contemporary humans are not fitted to the lifestyle and forms of social organization that exist in today’s post-agricultural, post-industrial societies - The vast majority of humans live in cities, towns and villages - The toxic ecology of urban lifestyles are generating ill-health and disease on a massive scale. - Early humans were hunter–gatherers  Spent less time working, building shelters and obtaining food than most humans after the agricultural revolution  Evidence suggests protein, mineral and vitamin intake among hunter- gatherers would have been generally about ‘recommended levels’  Leptin is a hormone produced by adipose cells, that inhibits food intake and increases energy expenditure in rodents  Ravussin et al. (1997) investigated whether individuals prone to weight gain are hypoleptinemic (i.e., they produce too little leptin)  Concluded low plasma leptin concentrations may play a role in the development of obesity in Pima Indians Hunters- Gatherers—Past and Present: - The hunter–gatherer hypothesis can be evaluated in the light of studies of contemporary hunter–gatherers - Four groups have been studied: • Australian aboriginals • the San (or ‘Bushmen’) of the Kalahari Desert, especially of the !Kung language group • pygmies in the Congo Basin • the Hadza of East Africa - Powles (1992) suggested that the average daily energy expenditure for a male in post-industrial society is more than 25% less than that among hunter–gatherers The Agricultural Revolution - About 10,000 years BP - Humans in the Middle East started living in densely populated villages and towns, cultivating wheat, barley and other cereals - Sheep and goats were kept in captivity and slaughtered for meat - The stabilizing influence of settlement also had adverse consequences: • Diet became less varied; • Levels of energy expenditure decreased; • Malnutrition, disease and infections became more prevalent; • Birth rate increased. The Industrial Revolution - 200 years ago - Modern digital inventions and labour-saving products have allowed for reductions in energy expenditure in tasks of daily living - The availability of Ready Meals, instant desserts and snacks means that food preparation is being moved from the domestic kitchen to the food-processing industry - Industry is slow to make improvements voluntarily - Health only becomes a higher priority than profit when there is a heavy consumer demand backed by policy and legislation. An Ecological Model: - Adiposity: fat content of the body and the fat content of foods, along with the relationship between the two - Principle systems involved in children’s eating habits: genetic environment, family environment, and larger community in which the child lives Fat and feeling fat - A pan-European survey about body image found disparity between ideal and current body image was generally greater for females than males (European Commission, 1999). - The obesity debate has focused on two main subjects: high fat foods and overweight people. - Triglyceride is the main component of dietary fats and oils and the principal form in which fat is stored in the body • Composed of saturated, monounsaturated and polyunsaturated acids - A high level of ‘bad’ cholesterol in the blood – hypercholesterolemia – is a risk factor for coronary heart disease - Low-density lipoprotein (LDL) is bad cholesterol; high-density lipoprotein (HDL) is good cholesterol - Excess weight of obese individuals is due mainly to adipose tissue mass of which 85% is fat - Individual models of obesity have placed the cause at one of two levels: • Individual overweight and obese people have been blamed for their ‘sloth’ and ‘gluttony’; • Overweight and obese people are assumed to have a genetic predisposition to lowered metabolic rate (Webb, 1995). The Toxic Environment - The ecological approach to obesity sees obesity in the context of the individual’s relationship to the surrounding environment - Three main influences on equilibrium levels of body fat—biological, behavioural and environmental - Obesity is seen not as a disorder of individuals requiring treatment but an expected consequence of living in an environment that is designed to produce obesity - Contemporary society is considered obesogenic because it generates too high an equilibrium level of fatness across the whole population - Fat balance equation: Rate of change of fat stores in body = rate of fat intake – rate of fat oxidation - Intake of fat is a significant component of total energy intake while total energy expenditure is the main determinant of fat oxidation - *Suburban areas are built with streets hard to negotiate on foot* • Shopping • Grocery stores • Parks - The average level of energy intake is falling more slowly than the average level of energy output. This imbalance has caused increases in average weight levels and prevalence of obesity - Without intervention at a policy level, the currently high prevalence of obese and overweight people is likely to remain evident for some considerable time. Environmental Influences on Food Choices - At the macro level are the consequences of policy, laws and regulations at a societal level - Micro level influences are at a family or individual level - The influences are also divisible into physical
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